I am an beginner with OpenGL and have just some pretty basic knowledge on programming.
I am working with an OpenGL based software like AutoCAD to create Rooms or Buildings
which inhibit Architecture of actual building Projects with every detail planned like build in
bathrooms, chairs, carpet, mirrors, desks with utilities on it. Windows, Doors, lights, tiles and so on.

Right now the software has 4 rendering engines one of em is a Raytracer. This way photorealistic
shots and videos are established. Something that's eternally missing is pleasurable background.

Putting in a jpg as background which is not even reacting to camera movements is not the way to do it.

Right now we are developing a game based export product of the buildings using unity-engine.

So later on on a unity in-browser solution the constructions will be realtime walkable.

I was looking for good and free game engines and was curious if it was possible to somehow
implement a gaming engine into the OpenGL CAD Software in the camera perspective window.
which itself is running in OpenGL.

The question would be if this is a technical challenge or easy to do theoretically.

Also the software will be rewritten in part for its x32->x64 relaunch next year.

Therefore it might be clever to wait until this is finished.

The main goal for me is grasp wether this is possible, what type of knowledge I will need to handle it,
and how long this will take.

In short:
The CAD Software should display in it's camera presentation mode of its project
also the world created by an gaming engine like Unigene, Unreal4 or Unity

There might be a lot of solutions how to do this,
or even simpler methods that use a hole different technique but this would be interesting for me to know.

If it's a bit to much to give an answer for this in detail
you are welcome to give me some sources to read
with short explanation what I can to with it.